1. Field of the Invention
This invention relates to hinge members for swingably mounting a door on a fixed structure the plane of which normally is disposed at an angle to the plane of the door and relates particularly to hinge members for mounting doors and the like on furniture and cabinets in which such hinge members are fully concealed when the door is closed.
2. Description of the Prior Art
Heretofore, hinges of various kinds have been provided for swingably mounting one member on another in a manner to permit relative movement. Most hinges have been provided with a pair of leaves having one or more loops or eyes which receive a hinge pin to connect the leaves togther. Normally where doors are concerned, one leaf is mounted on a fixed structure, such as a door frame, and the other leaf is mounted on the trailing edge of the door, while the hinge pin is spaced outwardly from the fixed structure and the door so that the door may swing relative to the fixed structure without interference. With this type of hinge, portions of each of the leaves and the hinge pin are exposed to view on the side toward which the door opens and since substantially all doors of furniture and cabinets open outwardly to afford access to the interior, such hinge portions have been clearly visible.
Some efforts have been made to conceal the hinges by providing apparatus having multiple pivots connected together by linkages, however, these efforts generally have been only partially successful. Normally the prior art efforts have attempted to reposition a primary pivot by a series of sequential motions which locate the primary pivot in a position to permit free swinging movement of the door. These prior attempts have had limited success due to one or more of the following practical difficulties:
1. Loss of door control. In most hinge members having multiple pivot parts, when the primary pivot has reached the desired position, the door is permitted to freely swing about the primary pivot. In such cases the door is free to contact the material of the frame. Also a loss of control problem arises when the structure loses control of the sequence of motions. Thus the sequence of motions does not depend on the linkages but depends on the vectors of force which initiate the opening and closing of the door.
2. Extension of the linkages. Often, in order to achieve a desired path of movement of the door, it was necessary for the connecting linkages to be extended a relatively large distance from the support structure. This permitted normal operating stresses to damage the hinge and resulted in hinges which were larger, heavier, and stronger than should have been required.
3. Failure to be fully concealed. Most of the prior art structures were at least partially visible when the door was closed.
4. Extensive modification of door and frame structure. Extensive door and frame machining or other modifications of an unusual character or beyond the accuracy standards of the industry were frequently required.
Some examples of the prior art are U.S. Pat. Nos. 2,018,909 to Anderson; 2,062,840 to Soss; 2,248,972 to Dumelin; 3,231,928 and 3,626,548 to Grunert.